Process for refining vegetable oils



-May 29, 1923.

C. H. HAPGOOD ET AL PROCESS FOR REFINING VEGETABLE OILS Filed June 29, 1921 HIHHH HHHHHIIIHIHHH y 3m, m .0 wfim w y a T4 r 0 P w G Patented May 29, 1923.

UNITED STATES 1,457,072 PATENT OFFICE.

' CYRUS HOWARD HAPG-OOD, OF NUTLEY, AND GEORGE FREEBCRN MAYNO, OF EAST ORANGE, NEW JERSEY, ASSIGNORS TO THE DE LAVAL SEPARATOR COMPANY, OF NEW YORK, N. Y., A CORPORATION OF JERSEY.

PROCESS FOR REFINING VEGETABLE OILS.

Application filed June 29, 1921. Serial No. 481,396.

To all whom it may concern:

Be it known that we, CYRUS HOWARD HAP- soon and GEORGE FREEBORN MAYNO, citizens of the United States, residing at Nutley and East Orange, respectively, county of Essex and State of New Jersey, have invented a new and useful Improvement in Processes for Refining Vegetable Oils, of which the following isa full, clear, and exact description, reference being had to the accompanying drawings, which, form a part of this specification.

The object of our invention is the refinement of vegetable oils. The invention is especially applicable to cottonseed oil, but is also applicable to any other vegetable oil containing impurities more readily saponifiable than the oil itself.

It is known to treat cottonseed oil with an alkali for the purpose of saponifying the fatty acid impurities in the oil and to then separate the oil from the soaps. One difiiculty arises from the circumstance that while the fatty acids are more readily sapo-nifiable than the oil, the oil itself is also saponifiable and hence there goes into soap stock a considerable proportion of the oil, both combined and free. As a constituent part of a soap stock the oil has ordinarily much less commercial value than when it is recovered as pure oil. It is recognized that it is desirable to so limit the duration of treatment with alkali and the strength of the alkali solution as to saponify only the fatty acids and avoid saponification of the oil, but the desideratum has not been achieved, nor is its attainment, in any absolute de ree, practicable.

The more specific object of our invention is to so treat the oil that the amount of oil that goes into soap stock will be reduced to a minimum. Another object of the invention is to materially increase the amount of oil that can be treated within a. given time. Another object of the invention is to so preliminarily treat the oil that it will be deprived of husks, dirt, e.to., before the oil is subjected to the treatment for removal of the readily saponifiable impurities. Another object of the invention is to combine our improved treatment for saponifying the fatty acids and eliminating the resultant soap with a final treatment adapted to complete clarification.

A valuable feature of our in'iproved procmix with the alkali.

ess consists in the fact that the operation preceding the final clarification treatment is a continuous operation as distinguished from a batch operation and that only a small quantity of oil,at any given time,.is being subJected to the saponificating and separat- 111% treatment.

he process is not dependent for its execution on any particular apparatus, but we have shown, in the drawings, a diagram of an apparatus adapted to carry out our process. the apparatus is composed are individually old, although they have not heretofore been associated together in the combination or sequence illustrated.

The separate oontrivances of which a represents a source of supply forcrude oil, say a tank car. The tank car is connected, by a valved pipe 6, with a rotary drum filteror screen. 0, the meshes of which are fine enough to prevent the passage through the screen of husks, shells, coarse dirt or other solid or flaky impurities that the crude oil may contain. The

'oil, with (usually) some fine dirt in suspension, passes through the screen into a trough d, from which the oil flows into a tank e which is of-relatively! large capacity, say'an eight thousand gallon tank; This tank is provided with, heating coils f to maintain the body of oil at a temperature at which it will be capable of flowing. Itv is custdma to heat the oil, prior to treatment with alkali,

to a temperature approximating 140 degrees F. in order to enable the oil, when treated in a large batch, to readily flow and It is possible, in our process, to heat the oilto ahigh temperature, but-such high heat treatment is very undesirable in that in our process, an emulsion would be formed that would be diflicult to break. We have found it possible to avoid heating the oil substantially above eighty degrees F., because in our process extreme fluldity is'unnecessary. We thus avoid the production of a substantial emulsion. The lower the temperature, the less of an emulsion will be formed and we therefore prefer a range of temperature between ei hty and one hundred degrees F. with a decided preference for the lower limit of such range.

9 represents a tank'for caustic soda or other alkali or sa onifying agent. This tank is of much sma ler capacity than the oil tank e, as the amount of alkali solution required to treat a. given quantity of oil is only (say) about eight per cent of the oil. The capacity of the alkali tank may therefore be about six hundred and forty gallons.

From the tanks and 9 lead valved pipes h and i to a funnel j communicating a mixer 10. This mixer is of such size and the outflow therefrom is soregulated that the mixture of oil and alkali will flow through it in about eight or ten minutes. The duration of treatment, however, may vary from five to fifteen minutes'or even within a somewhat wider range of time. The mixer contains fixed and rotatable elements whereby the oil and alkali are subjected to mechanical agitation so as to effect a primary sapouification of the fatty acids.

From the mixer the mixture flows to a centrifugal separator m, which preferably is of the type shown in the Snyder Patent No. 1,283,343, dated October 29, 1918. In the separator there is a transitory stage of further admixing which, while of very short duration, occurs while the mixture is finely broken up, thereby allowing an intimate contact of free alkali with the fine fatty acid particles. The heavy alkali and soap stock (which at this stage is in a very fine break or separated condition) moves outward to the eriphery, displacing the lighter oil inwardv, the oil being floated oil through discharge spout n and the heavier ingredients discharging through the sludge spout 0 into a pipe p leading to a soap stock receptacle (not shown). The soap stock comprises chiefly combined alkali and fatty acid and contains very little oil either in combined or free form.

The oil, which is practically free of soap, is discharged into a pipe 8 leading to a tank t, which preferably has a capacity aboutequal to that of the oil tank e. To this tank is added an inert substance adapted to act as a clarifying or bleaching agent, such as fullers earth. When the entire volume of oil in the tank e has been treated as described (orduring the inflow of the oil into the tank t), a shaft, carrying the blades u, is kept in rotation so as to thoroughly mix the fullers earth with the oil. The mixture is then forced, by means of a pump 12, into a filter press w, from which the perfectly clarified oil is discharged into a pure oil reservoir at. I

It will be understood that in the drawing the relative size of the centrifugal separator is considerably exag rated.

The percenta an strength of the caustic alkali employ in the process. depends on the grade of crude oil being treated. With a prune crude oil containing from .8 to 2 per cent. free fatty acid, caustic alkali of six or seven r cent of ten. degrees Baum can be u successfully.' With oils of poorer a stronger degree and quality and higher in fatt acid an alkali of igher percentage must be used. The percenta e of fullers earth may be about one-fourt of one per.

cent.

Having now fully described our invention, what we claim and desire to protect by Letters Patent is:

1. A continuous 'process for refining vegetable oils which comprises filtering out saponification of the fatty acids followed by separation of the saponifying agent and soaps from the oil, agitating the oil with an inert clarifying agent and filtering the oil.

2. A continuous process for refining vegetable oils which comprises flowing a stream of a saponifying agent into contact with a flowing stream of oil, subjecting the mixture during the flow to a mechanical mixing action in such small quantity and for so short a time asto effect a primary saponification of the fatty acids without saponification of a substantial roportion of the free oil, andsubjecting the flowing mixture of oil and soap to centrifugal force to effect a relatively very short but more intimate admixture of the constituents with a resultant secondary saponificationof the fatty acids followed by separation 'into layers and continuously floating oil the oil and discharging the soaps, thereby effecting a maximum saponifica tion of the fatty acids with a minimum saponification of oil.

3. A continuous process for refining vegetable oils which comprises flowing a stream of a saponifying agent into contact with a flowing stream of an oil and during the flow of the mixture subjecting it to a mechanical mixing action of suflicient duration to effect a saponification of. the fatty jecting the mixture of oil and soap to cen-.

trifugal force, floating off the oil, treatin the 011 with an inert clarifying agent an separating the oil therefrom.

4. A continuous process for refining -vegetable oils which comprises flowing a stream of oil maintained at a temperature of not less than approximately eighty degrees F. and not higher than ap roximately one hundred degrees F. and uri'ng the flow of the mixture subjecting the same first to a mechanical agitation with a saponi ing agent for a time sufiicient to saponi a substantial pro ortion of the fatt acids without saponi cation of a substantial proportion of the free oil, and then to centrifugal force and floating ofi the oil.

5. A continuous process for refining vegetable oils which comprises flowing a stream of oil maintained at a temperature of not less than approximately eighty degrees F. and not higher than approximately one hundred degrees F. and during the flow of the mixture subjecting the same first to a mechanical agitation with a saponifying agent for a time suflicient to saponify a substantial proportion of the fatty acids without saponification of a substantial proportion of the free oil, and then to centrifugal force, floating ofi' the oil, treating the oil with an "inert clariftying agent and separating the oil there rom.

6. A continuous process for refining vegetable oils which comprises maintaining a body of oil and a bod of a saponifying agent, flowing from eac tially continuous stream at a regulatable rate, mixing said streams, maintaining admixed at any given time a volume of the mixture that is small relatively to the volbody a substan-' ume of the original body of oil and for a hereunto set-'our hands, at New York, on

this 31st day of May, 1921.

CYRUS HOWARD HAPGOOD. GEORGE FREEBORN MAYNO.

Witnesses:

HERBERT K. WILLIAMS, R. R. WARREN. 

